What Do Integrators Need to Know about DisplayPort 1.4?
I had a chance to connect recently with Marques Girardelli, manager of electronics platforms at Planar and Leyard for an in-depth discussion on connectivity trends. We started with the basics: DisplayPort 1.4.
Wait a minute. What happened to DisplayPort 1.3?
The DisplayPort 1.3 specification was published in 2014, superseding the DisplayPort 1.2 specification from 2009. New features include the following:
- 50% bandwidth increase, allowing for 8K @ 30Hz signal transmission
- 2020 (or BT.2020) colorimetry
- HDCP 2.2 support
- 4:2:0 color subsampling
Adoption of DisplayPort 1.2 was relatively slow, as technology challenges hindered the implementation of the higher bandwidth. With DisplayPort 1.3, although many chip manufacturers are working to add support for the new features, adoption has faced similar challenges. The DisplayPort 1.4 standard release further complicated efforts to bring DisplayPort 1.3 to market. The good news is that DisplayPort 1.4 doesn’t increase the overall transmission bandwidth, meaning that all of the work done on DisplayPort 1.3 will be carried forward. Consequently, the market will jump from DisplayPort 1.2 to 1.4, skipping DisplayPort 1.3 entirely. So, now that you know all about DisplayPort 1.3, you can forget it.
What are the new features in DisplayPort 1.4?
There were two main objectives of DisplayPort 1.4:
(a) add support for 8K @ 60Hz, and
(b) play catch up with HDMI 2.0.
To match the HDMI 2.0 feature set, support for 32-channel audio and HDR was included. However, the biggest change is the addition of a visually lossless compression scheme called Display Stream Compression, or DSC. By performing light compression on the video data, the bandwidth can be increased by up to 3x, enough to support 8K @ 60Hz. Expect to see DisplayPort 1.4 products with DSC support starting in 2017 or 2018. However, most of the benefits of DisplayPort 1.4 won’t be realized without an 8K display.
What about cable lengths?
It is important to note that DisplayPort technology can’t achieve the same cable lengths that HDMI can. At full bandwidth, expect to only get 2-3 meters of performance, with some source/display combinations working up to 5 meters. If a long cable run is necessary, consider a cable extension solution, such as a fiber optic cable.